Lab 2 Plate Tectonics and Ocean Geography

Transcription

1 Name Part I Plate Boundaries 1. On the above map of Earth s lithospheric plates, a convergent boundary means a) plates move toward each other b) plates move away from each other c) plates slide past each other. An oceanic convergent plate boundary is associated with what prominent geographic feature? List the names of 4 of these features at in the Pacific Ocean. a. b. c. d. The saw-toothed symbol parallels the west coast of South America and the Andes Mountain Range. Describe what happens to the eastern edge of the Nazca Plate as it approaches the South American Plate. A continental margin with an offshore subduction zone/trench is called a (circle) Passive Margin Active Margin 1

2 2. Note the east margin of the North American Plate and the South American Plate. Where are their eastern margins located?. Where are the western margins of the African and Eurasian Plate boundary?. The Mid -Atlantic Ridge is called a Divergent Plate Boundary. Why? 3a. With respect to lithospheric plates, how does the Atlantic Ocean differ from the Pacific Ocean? 3b. With respect to continental margins, how is the Atlantic Ocean distinct from the Pacific Ocean? Hint: What is the difference between a passive and an active continental margin? See profiles Lab I 2

3 4a. Japan is an island arc produced by the subduction of the plate into the Japan Trench. Draw sawteeth along the Japan Trench, teeth point landward. 4b. List the 4 lithospheric plates of Japan s complex tectonic geography c. What geologic hazard(s) are associated with these convergent boundaries? 5a. What is the name of the subduction zone/trench closest to Miami, Florida. What two plates converge here? 6. Name the type of plate boundary (divergent, convergent, transform) between the Pacific Plate and North American Plate at the following locations: Southern California Northern California-Oregon-Washington Aleutian Islands Alaska 3

4 Part II. Seafloor Spreading Your instructor has lithospheric plate/divergent boundary models. Working in groups of three or more, assemble a model so that Plate A (continental lithosphere) and Plate B (continental lithosphere) are joined as one continent this configuration is the 15 million years ago when there was one continent position. (Seafloor tabs will be fully inserted trailing out the underside). Full spreading rate (show calculations below) 4

5 6) Note the African Rift Valley. (page 1) This is understood to be a young spreading center. How will the geography of Africa have altered 15 million years from the present? 7) Locate Madagascar on the map. Within the context of a discussion of seafloor spreading and continental drift what might you suggest about Madagascar s tectonic history? 5

6 Part III Rocks forming Continental Crust & Rocks forming Oceanic Crust 1) 2) The density of oceanic rocks is higher or lower than that of continental rocks? (circle) Higher Density Lower Density Continued 6

7 Part IV Locating Features of Earth s Oceans Use the map on page 1 of this lab and the map your instructor will provide for in-lab use. A copy of the classroom map is included for you on last two pages of this lab. Pacific Ocean Atlantic Ocean Indian Ocean P1 East Pacific Rise A1 Argentine Abyssal I1 Carlsberg Ridge Plain P2 Mendocino Fracture A2 Mid -Atlantic Ridge I2 Seychelles Islands Zone P3 Galapagos Islands A3 Bermuda Rise I3 Arabian Sea P4 Mariana Trench A4 Walvis Ridge I4 Kerguelen Island P5 Peru-Chili Trench A5 Puerto Rico Trench I5 Madagascar P6 Sea of Okhotsk A6 Scotia Sea or Ridge I6 Red Sea P7 Bering Sea A7 Falkland Islands I7 Persian Gulf P8 Kermadec-Tonga Trench P9 Emperor Sea Mount Chain P10 Island of Hawaii P11 Aleutian Trench P12 Nazca Plate P13 Juan de Fuca Plate P14 Great Barrier Reef A8 Iceland I8 Ninety East Ridge ( 90º E Ridge ) A9 Canary Islands I9 Java Trench A10 Labrador Sea 7

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